Microsoft has moved to seize the Halo 4 beta website it warned fans was a fake.
Microsoft has filed a complaint with the National Arbitration Forum against Halo4beta.net, which 343 Industries' David Ellis said on his Twitter page was a fake.
Microsoft bought the domain name Halo4.com last year. It redirects to the Halo 4 page on Xbox.com.
The hotly-anticipated Xbox 360 exclusive launches this Christmas.